This invention relates to a device for measuring the degree of spinal deformity in patients having scoliosis. The widespread use of school screening programs for the early detection of spinal deformity has significantly reduced the need for spinal fusion because effective nonoperative measures can be used if the deformity is found before it becomes severe. However, a problem has been created by these programs, namely, over-referral of great numbers of children with very mild curvatures which do not require treatment.
Because no objective criteria for referral have been established, the number of children referred by the screening process depends upon individual experience or technique of the referring nurse or technician. There is a wide variability in the reported incidence of scoliosis in school children, ranging from 1 to 16 percent. These figures must be viewed in relationship to the accepted incidence of scoliosis in the adult population, which is approximately 2 percent, and the estimated number who actually require treatment, which is 0.2 percent. Such over-referral clearly results in unnecessary x-ray examinations and needless expenditure of health care dollars and points to the need for a more selective screening method.
A number of clinical methods have been used in the past to document the clinical deformity in scoliosis. The most commonly used method employs a spirit level and ruler to measure the height of the "rib hump" at the apex of the deformity. This has the disadvantage of being cumbersome, and also fails to take into account the size of the patient in determining the significance of the rib deformity.
Contour devices may be used to transfer the outline of the deformity to a sheet of paper or back of an x-ray folder. These methods are somewhat inconvenient and have not gained widespread use.
More recently, moire fringe topography has been used as a method for both screening and follow-up examinations. While the method may be quite accurate, the apparatus is costly and requires space for a permanent setup, personnel to operate it, and, ideally, a computer to analyze and store information.